What is the yellow symbol the Australian players have on their shirt collars in this Ashes series?

Has anyone made a higher score than Steve Smith's 142 at Edgbaston that wasn't his own highest score of the match? asked Tim Clements from England
That superb double by Steve Smith at Edgbaston earlier this month was only the fourth time a batsman had exceeded 140 twice in the same Test. Andy Flower followed 142 in Zimbabwe's first innings against South Africa in Harare in 1999-2000 with 199 not out in the second innings, while Tillakaratne Dilshan hit 162 and 143 for Sri Lanka against Bangladesh in Chittagong in 2008-09. But the leader on this particular list is Australia's Allan Border, the only man to reach 150 twice in the same Test: against Pakistan in Lahore in 1979-80 he made 150 not out in the first innings and 153 in the second.

The commentators were getting very worried that Jofra Archer was being overbowled at Lord's. What's the longest spell by a fast bowler in a Test? asked Michael Roberts from England
Jofra Archer's promising spell, during his debut Test, at Lord's, lasted all of nine overs, seven of them on the third morning. That's some way from the longest-known spells by seamers: John Lever bowled 31 successive overs for England against Australia in Melbourne in 1979-80 (he finished with 4 for 111 from 53), as did Australia's Mick Malone, in his one and only Test, at The Oval in 1977, while Kapil Dev's career-best 9 for 83, for India v West Indies in Ahmedabad in 1983-84, came in one unbroken run of 30.3 overs. Charles Davis, the eminent Australian statistician, also unearthed a spell by the early Aussie "demon bowler" Fred Spofforth, against England in Sydney in 1884-85, that lasted 48 four-ball overs, the equivalent of 32 six-ballers.

The longest spell I can find by a genuinely quick bowler is one of 24 overs by Wes Hall of West Indies on the pulsating final day of the 1963 Lord's Test, which ended with England needing six to win and their last pair at the crease. "Hall, in particular, and [Charlie] Griffith, showed remarkable stamina," reported Wisden. "Hall bowled throughout the three hours and 20 minutes that play was in progress on the last day, never losing his speed and always being menacing. He took four for 93 off 40 overs in the innings. Griffith bowled all but five overs on the last day."

What is the symbol, like a big golden flower, on the Australian players' shirt collars in this Ashes series? asked Chris Ricketson from Australia
The collar embellishment is actually a representation of a piece of Australian native art called "Walkabout Wickets", by Aunty Fiona Clarke, the great-great-grand-daughter of "Mosquito", a member of the pioneering Aboriginal team that toured England in 1868. According to Cricket Australia, the shirt symbol is a commitment as a team to reconciliation and finding common ground with Aboriginal and Torres Strait Islander peoples.

The artwork represents past, present and future Aboriginal cricketers. The large circle represents Lord's, one of the many famous grounds the 1868 team visited, while the smaller circles signify the team's various meeting places. The wickets appear with no bails, to illustrate that the game continually moves on. And the flying stumps represent Aboriginal cricketers beating the English at their own game.

Did Dale Steyn have the best bowling strike rate in Test cricket? asked Joel Pojas from the Philippines
The answer here depends on the qualification you impose. Dale Steyn leads the way for those who took more than 200 Test wickets, as his 439 victims came at a rate of one every 42.3 balls; next are Waqar Younis (43.4), Malcolm Marshall (46.7) and Allan Donald (47.0). But watch out for Steyn's South African team-mate Kagiso Rabada: so far he has taken 176 wickets at a strike rate of 38.8.

If you drop the qualification to 100 Test wickets, then Rabada is second and Steyn fourth. The 19th-century Surrey seamer George Lohmann tops the list: he took his 112 wickets at a rate of one every 34.1 balls. Another legendary England bowler, Sydney Barnes, collected 189 wickets at a strike rate of 41.6.

Who was the man who, in his first Test as an umpire, gave Sunil Gavaskar out first ball? asked Hang Zhang from Australia
The umpire who was called into action immediately in his first Test was the jovial England-based Aussie Bill Alley. He confirmed that Gavaskar had been caught behind - by Alan Knott off Geoff Arnold - from the very first ball of the match between England and India at Edgbaston in 1974.

Said Wisden: "Alley was the first Australian-born umpire to stand in a Test in England since Jim Phillips in 1905. Moreover, off the first ball of the match Alley gave out Gavaskar caught at the wicket, and off the last ball Engineer leg-before."

This was the first of Alley's ten Tests in the white coat. He joined Somerset in the 1950s after missing out on Test cricket at home, and in 1961 - aged 42 - became the last man to date to amass 3000 first-class runs in an English season, a feat that will never be repeated unless there is a substantial change to the current fixture list.

And there's an addition to the recent question about England openers from the same county, from Rajiv Radhakrishnan
"The Surrey pair of Mark Butcher and Alec Stewart [who was his brother-in-law at the time] opened the batting for England in Sydney in 1998-99, and in the first two Tests against New Zealand at home the following summer. So they are the most recent pair from the same county, before Rory Burns and Jason Roy, also of Surrey, this year."